More specifically, this invention relates in particular to that type of known machine which operates either intermittently or continuously to package articles in pieces of sheets of in particular a heat-shrinking material comprising essentially a wrapping conveyor having a feed end, a delivery end and an upper surface between the two ends to support and convey successive articles which need to be wrapped; means to feed the wrapping material to supply single pieces of wrapping material in succession to the wrapping conveyor wherein the anterior ends of these pieces are above the upper surface of the wrapping conveyor at the feed end; conveyor belt means to deliver and receive the articles placed adjacently in sequence respectively but at a distance from the corresponding feed and delivery ends respectively of the wrapping conveyor; endless conveyor means carrying at least one wrapping bar along a track which passes around the wrapping conveyor to wrap the pieces of sheet of heat-shrinking material about a corresponding article on the wrapping conveyor; and means capable of synchronising the said wrapping conveyor, the means for supply of the wrapping material, the means for delivering and receiving articles and the endless conveyor and wrapping means with a bar in a synchronised manner.